I disagree with some who have said that Friendship and or Love is unconditional. We all place conditions, large and small, on our friends and loved ones. If I had a friend or loved one who became disagreeable, or was late or didn't show up most of the time, became a slob, wasn't honest or who started doing things or supporting something I though was wrong, I might choose not to associate with him anymore until he changed.
Your friend wants you to be what she wants you to be. You knew her via the JW's and she wants you to be like you were back then, however you have grown up and are not the idealistic and easily impressed 19 year old you once were and that's normal, you're not supposed to be.
She has every right to place her own conditions on her side of the friendship but you don't have to buy into the idea that just because this woman that you're viewing with your 19 year old eyes doesn't agree with your choices, you re the problem in this situation.
I think her letter was condescending, manipulative and full of those odd JW catch phrases designed to make the user (her) sound and feel as if they are on a higher more virtuous plane than the the recipient (you). She liked you better back in the day when using them on you had the desired effect.